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This Article Full Text Full Text (PDF) All Versions of this Article: 290/6/H2385    most recent 01207.2005v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via ISI Web of Science (7) Citing Articles via Google Scholar Google Scholar Articles by Segers, P. Articles by Verdonck, P. R. Search for Related Content PubMed PubMed Citation Articles by Segers, P. Articles by Verdonck, P. R.

Aortic reflection coefficients and their association with global indexes of wave reflection in healthy controls and patients with Marfan's syndrome

¹Cardiovascular Mechanics and Biofluid Dynamics, Institute of Biomedical Technology, Ghent University; Departments of ²Medical Genetics, ³Cardiovascular Medicine, and ⁴Medical Imaging, and ⁶Heymans Institute of Pharmacology, Ghent University Hospital, Ghent, Belgium; and ⁵Institute for Surgical Research, Rikshospitalet University Hospital, Oslo, Norway

Submitted 15 November 2005 ; accepted in final form 2 January 2006

Early return of reflected pressure waves increases the load on central arteries and may increase the risk of aortic rupture in patients with Marfan's syndrome (MFS). To assess whether wave reflection is elevated in MFS, we used ultrasound and MRI to measure central pressure and flow waveforms in 26 patients (13–54 yr of age) and 26 age- and gender-matched controls. Aortic systolic and diastolic cross-sectional areas were measured at the ascending and descending aorta (AA and DA), diaphragm (DIA), and lower abdominal aorta (AB). From these measurements, local characteristic impedance (Z_0-xx) and local reflection coefficients (_xx-yy) were calculated. Calculated global wave reflection indexes were the augmentation index (AIx) and the ratio of backward to forward pressure wave (P_b/P_f). The aorta was wider in MFS patients at AA (P < 0.01) and DA (P < 0.01). Aortic pulse wave velocity was 42 cm/s higher in MFS patients (P < 0.05). Z_0-xx was not different between groups, except at DA, where it was lower in MFS patients. In controls, _AA-DA was 0.31 ± 0.08, _DA-DIA was 0.00 ± 0.11, and _DIA-AB was 0.31 ± 0.16. Mean values of _xx-yy were not different between MFS patients and controls. In controls, aging diminished _AA-DA but increased _DIA-AB. Clear age-related patterns were absent in MFS patients. AIx or P_b/P_f was not higher in MFS patients than in controls. There were indications for enhanced wave reflection in young MFS patients. Our data demonstrated that the major determinants of AIx were pulse wave velocity and the effective length of the arterial system and, to a lesser degree, HR and P_b/P_f.

magnetic resonance imaging; augmentation index